Interpreting CEA Levels

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I have stage 4 colon cancer. At the beginning of chemotherapy, my CEA number was 180. After two series of chemo, the CEA number is 2.0. I know it doesn't mean that I'm cancer free, but can you tell me what it really means? Does it mean remission? Typically, how long am I likely to stay at that level? (2.0)

James M. Metz, MD, Editor-in-Chief of OncoLink and Assistant Professor of Radiation Oncology at the Hospital of the University of Pennsylvania, responds:

CEA is a type of tumor marker, which is a substance that is produced by the body in response to cancer or produced by cancer itself. These “markers” are not always specific to one cancer and in many cases are present at lower levels without cancer being present or elevated due to other conditions. (Read more about tumor markers.)

When we follow patients after treatment for colon cancer, physicians look at a variety of parameters to determine if someone is free of disease. This includes evaluating any symptoms, performing a complete physical exam, getting regular radiologic scans, colonoscopies and following specific blood work. The CEA in your case is one part of the puzzle. It is not a good screening test, but very helpful in following patients that have undergone treatment when it was initially elevated. It is excellent news that the CEA has decreased from 180 to 2. The CEA is a good marker to follow in your case to determine disease activity. Most importantly we look at trends. The CEA can bounce up and down a little, but an upward trend over time in multiple measurements could mean something is going on that would require additional tests. There is no magic
number of how long it is expected to stay at that level. However, we hope it does as long as possible or permanently.